Manufacture of hour signs for watch and clock faces



w. KOCHLI 3,323,396

MANUFACTURE OF HOUR SIGNS FOR WATCH AND CLOCK FACES June 6, 1967 Filed May 13, 1965 FIG-.1 F|G.2 F'|G.3

PIC-3.7

3 "III United States Patent 3,323,396 MANUFACTURE OF HOUR SIGNS FOR WATCH AND CLOCK FACES Willy Kochli, La Chaux-de-Fonds, Switzerland, asslgnor to Jean Singer & Cie S.A. Filed May 13, 1965, Ser. No. 455,503 Claims priority, application Switzerland, May 13, 1964, 6,212/ 64 Claims. (Cl. 821) Methods of manufacture are already known for producing portions of watch or clock parts, starting from sections in roll form selected as a function of the shape to be given to the blank of the part, the extremity of which is machined by displacement of a tool along an axis parallel to that of the section, the machined end then being sliced in order to detach from the section the blank obtained. These operations can be elfected automatically upon a machine tool specially designed for this purpose.

It is also known that timepiece dials are frequently provided with hour signs attached to the face, and fixed to the latter by means of cylindrical feet. One method of manufacturing such hour signs consists in stamping a metal plate so as to cause two feet to project therefrom, and then centering the band by the feet so shaped so as to cut out the outline of the sign. The stamping and cuttingout tools and equipment necessary for carrying out this process are delicate, and the waste of material (usually gold) is considerable.

Up to the present no one has had the idea of manufacturing attached hour signs in a succession of automatic operations, starting from a section. In point of fact, hour signs require a very high degree of finish, which a standard section could not ensure, and the varied forms that they represent could only be obtained by means of complicated equipment. Hence machine tools that might have been constructed specially for this purpose, in a manner analogous to those known for the manufacture of portions of time-piece parts, would have presented an excessive complexity, and would have seriously burdened the cost of manufacture of the hour signs.

The present invention relates specifically to a method of manufacturing hour signs for time-piece faces by means of an automatic lathe with a movable tail-stock and a multi-spindle head-stock, obviating these disadvantages.

This method is characterised by the fact that on the movable tail-stock is mounted a metallic section the profile of which corresponds to the blank of the sign, placed lengthwise, by means of a tool at the extremity of the bar, that the bar is then immobilised in an angular position determined in relation to the axis of rotation of the movable tail-stock, that the feet of the sign are then individually machined in succession by means of a tool mounted on at least one of the spindles of the head-stock, and finally that the section is sliced to the ultimate dimensions of the sign by means of a milling cutter mounted upon one spindle of the head-stock, the section being then restored to its lengthwise position in order to obtain the following sign.

One form of construction of the sign obtained by the present method is illustrated by way of example in the accompanying drawings, together with the stages of its operation.

FIGURES 1, 2 and 3 show a finished sign in profile, in plan and in elevation respectively; and

FIGURES 4 to 7 illustrate diagrammatically the stages in the machining of such a sign starting from a metallic section.

For carrying out this process, use is preferably made of an automatic lathe with a movable tail-stock and with a multi-spindle head-stock, for instance a lathe of the type known by the trade mark Tornos, which is capable of being used for a number of standard machinings.

To obtain completed hour signs, such as those represented in FIGURES 1 to 3, comprising a body 1 and fixing feet 2, a start is made from a metallic section, usually of precious metal, drawn so as to present a cross section corresponding to the blank of the sign, and to provide a sign having a surface of fine-grained homogeneous structure. Starting from this section, each of the signs is machined and sectioned successively, so that as the section advances over the lathe, the signs can be produced in series.

In a first stage, the section 3 is introduced into the movable tail-stock of the lathe, which is not shown. This movable tail-stock is provided with a cam having two notches apart, and enabling the section carried by the tailstock, to be immobilised 'by means of a locking member, either in the position illustrated in FIGURES 5 and 6 or in that illustrated in FIGURE 7. A radial lathe tool 4 then restores lengthwise the extremity 3a of the section of axis A-A, so as to obtain a smooth front surface, and to fix precisely the height of the machined sign. The tail-stock is then immobilised in the position of the section indicated in FIGURES 5 and 6.

In a second stage, as represented in FIGURE 5, one of the spindles of the head-stock, not shown, carrying a rotary lathe tool 5, turns, on the front face of the section 3, a foot 2a, the axis BB of which is parallel to that of the section and merges into that of the said spindle. The head-stock then shifts so that the rotary lathe tool 6 of another spindle turns the foot 2/), with an axis C-C' (FIGURE 6). This stage may optionally be followed by machining facets tangential to the upper face of the finished sign, by means of other spindles of the headstock, bearing suitable tools.

In a third stage, diagrammatically represented in FIG- URE 7, a last spindle, of axis D-D', of the head-stock, carrying a milling cutter 7, connected with a disc 7b by a sleeve 70, is placed in a plane perpendicular to the axis of the section, and slices the latter, so as to give to the completed sign its correct height. The disc 7b is designed to retain the sign during the operation of slicing the section. The sign then falls into the trough of the machine. The dividing may of course be effected in a plane which is not perpendicular to the axis of the section. In the example of FIGURE 7 the section, as a preliminary step, has been rotated through a quarter of a revolution with the headstock, so as to present its smallest dimension towards the milling cutter.

The signs thus machined have their final dimensions. Only a surface polishing is still necessary in order to give them their full brightness.

The tools utilised for machining the signs might of course .'be different. The rotary lathe tools would admit of being replaced by bell-shaped milling cutters. It would likewise be possible, by an accessory operation, to hollow out the extremities of the feet of the signs, so as to facilitate riveting them to the dial.

What I claim is:

1. Process of making hour indicia for time piece dials by means of an automatic lathe having a movable turret and a multi-spindle counter-turret, comprising the steps of mounting on the movable turret, a metallic section having a cross-section corresponding to the shape of the rough cut indicium, positioning the metallic section in a lengthwise direction by means of an index at the end of the metallic section, then immobilizing said metallic section in a selected angular position determined with reference to the axis of rotation of the movable turret successively machining each of a plurality of feet of the indicium by means of at least one tool mounted on at least one of the spindles of the counter-turret and then cutting off the metallic section to definite dimensions of the indicium by means of a cutting tool mounted on a spindle of the counter-turret, the metallic section being then moved lengthwise to a new position for production of the next indicium.

2. Process according to claim 1, in which the tool for machining the feet is rotated about an axis parallel to but ofiset laterally from the longitudinally axis of said metallic section.

3. Process according to claim 2, in which the tool for machining the feet is of trapezoidal shape with one edge parallel to the axis of rotation of the spindle carrying the tool and another edge inclined to said axis of rotation.

4. Process according to claim 1, in which the metallic section is rotated approximately 90 about its longitudinal axis after machining of said feet and before cutting off the metallic section 5. Process according to claim 1, in which the cutting off of said metallic section is effected with the longitudinal axis of the metallic section inclined to the axis of the cut off tool in a manner to provide an inclined facet on the visible face of the indicium.

No references cited.

WILLIAM W. DYER, J R., Primary Examiner.

LEONIDAS VLACHOS, Examiner. 

1. PROCESS OF MAKING HOUR INDICIA FOR TIME PIECE DIALS BY MEANS OF AN AUTOMATIC LATHE HAVING A MOVABLE TURRET AND A MULTI-SPINDLE COUNTER-TURRET, COMPRISING THE STEPS OF MOUNTING ON THE MOVABLE TURRET, A METALLIC SECTION HAVING A CROSS-SECTION CORRESPONDING TO THE SHAPE OF THE ROUGH CUT INDICIUM, POSITIONING THE METALLIC SECTION IN A LENGTHWISE DIRECTION BY MEANS OF AN INDEX AT THE END OF THE METALLIC SECTION, THEN IMMOBILIZING SAID METALLIC SECTION IN A SELECTED ANGULAR POSITION DETERMINED WITH REFERENCE TO THE AXIS OF ROTATION OF THE MOVABLE TURRET SUCCESSIVELY MACHINING EACH OF A PLURALITY OF FEET OF THE INDICIUM BY MEANS OF AT LEAST ONE TOOL MOUNTED ON AT LEAST ONE OF THE SPINDLES OF THE COUNTER-TURRET AND THEN CUTTING OFF THE METALLIC SECTION TO DEFINITE DIMENSIONS OF THE INDICIUM BY MEANS OF A CUTTING TOOL MOUNTED ON A SPINDLE OF THE COUNTER-TURRET, THE METALLIC SECTION BEING THEN MOVED LENGTHWISE TO A NEW POSITION FOR PRODUCTION OF THE NEXT INDICIUM. 